hpux man page for xnextrequest

XNextRequest()															    XNextRequest()

Name
  XNextRequest, NextRequest - return serial number of next request.

Synopsis
  unsigned long XNextRequest(display)
	  Display *display;

Arguments
  display   Specifies a connection to an X server; returned from XOpenDisplay().

Returns
  The serial number.

Description
  XNextRequest()  extracts the full serial number that Xlib will use for the next request.  Serial numbers are maintained separately for each
  display connection.

  The C language macro NextRequest() is equivalent and slightly more efficient.

See Also
  XLastKnownRequestProcessed().

Xlib - Macro Equivalents													    XNextRequest()